Erjon Bogdani's second-half goal handed Cesena victory in their battle to avoid relegation while it placed Bari one step closer to Serie B.
Bodgani struck in the 48th minute to allow Cesena to leapfrog Sampdoria into 17th in the standings.
The result has left Cesena one place and two points clear of the drop zone with five games remaining.
Bari, meanwhile, remain at the foot of the standings, 13 points adrift of safety.
Bari dominated the opening stages and would have taken an eighth minute lead had Cesena goalkeeper Francesco Antonioli not made a good save from Abdelkader Ghezzal's 30-yard effort.
Shortly after, Gergely Rudolf fired just wide of the far post from the six-yard box.
In the 18th minute, Bari had a great opportunity to move in front when Sergio Almiron fed Rudolf inside the area and his diagonal shot was met by a fine save from Antonioli.
Cesena first tested Bari goalkeeper Jean Francois Gillet in the 26th minute.
Alessandro Rosina's bullet strike from long range was kept out by Gillet.
On the stroke of half-time, Emanuele Giaccherini's powerful header from Rosina's cross forced Gillet to fully stretch to clear.
Cesena picked up where he left off after the re-start and took a deserved lead.
Giaccherini fed Bogdani inside the area and his right-footed strike beat Gillet.
Bari pressed forward in search of the equaliser and had several chances.
In the 64th minute, Alessandro Parisi fired just wide from outside the area with Antonioli already beaten.
One minute from time, Simone Bentivoglio found Emmanuel Rivas inside the area and he fired over the bar from a good position.
Cesena held on for a vital win in their fight to avoid the drop.